Lasius productus

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Endemic to Japan – found on Honshu, Shikoku, Kyushu, and Tsushima islands in broad-leaved deciduous forests at elevations from 50-1000 m ^[2][3]. Nests in rotting wood, stumps, and dead portions of tree trunks, often around root systems or inside hollow tree trunks ^[1][3][2].
• Colony Type: Single-queen colonies (monogyne), typical of the subgenus Lasius s.str. ^[3]. Ergatoid replacement queens have not been documented.
• Size & Growth:
  • Queen: Unknown – no total length measurement recorded, scape length (antenna segment) over 1.4 mm, far larger than other Japanese Lasius ^[3].
  • Worker: 3.5-4.5 mm total length ^[1].
  • Colony: Not documented in research, no maximum colony size has been reported.
  • Growth: Moderate – development timeline unconfirmed but likely 8-12 weeks based on related species.
  • Development: Estimated 8-12 weeks at optimal temperature (inferred from related Lasius). (Direct data unavailable, estimate based on genus-level patterns for Lasius s.str.)
• Antkeeping:
  • Temperature: Keep at room temperature, around 20-25°C, consistent with its forest habitat. A gentle gradient allows self-regulation.
  • Humidity: Keep the nest substrate consistently moist but not waterlogged. Their natural nests in rotting wood retain moisture well ^[1][2].
  • Diapause: Yes, based on its temperate Japanese habitat. Provide 3-4 months at 5-10°C during winter (November-February in the Northern Hemisphere). This is inferred from typical Lasius s.str. requirements ^[3].
  • Nesting: Y-tong (AAC) or plaster nests with narrow chambers scaled to their worker size (3.5-4.5 mm). Natural setups with rotting wood pieces also work well ^[1][2].
• Behavior: Generally peaceful – they forage primarily for honeydew from aphids and hunt small insects. Like other Formicinae, they spray formic acid as a defense, they do not sting ^[4][5]. Workers are active in the evenings and at night. Escape risk is moderate due to their small size: use standard barriers like Fluon or tight-fitting lids.
• Common Issues: colonies may fail without proper winter diapause – this is inferred from their temperate distribution., escape prevention is necessary but standard barriers (Fluon, tight lids) are sufficient., founding queens are not directly observed in research, follow typical claustral procedures but be prepared for possible delays., humidity management critical – too dry causes brood loss, too wet promotes mold., wild-caught colonies may carry parasites, quarantine is recommended.

Nest Preferences and Housing

In the wild, Lasius productus nests in rotting wood, stumps, and dead portions of tree trunks within broad-leaved deciduous forests ^[1][2]. They often build nests around root systems of living trees or inside hollow trunks ^[3]. For captive care, Y-tong (AAC) or plaster nests with narrow chambers work well. Scale the chambers to their worker size (3.5-4.5 mm). You can also use natural setups with pieces of rotting wood. Provide darkness and privacy – these ants prefer sheltered spots. A test tube setup is suitable during founding, with a move to a formicarium once the colony exceeds 30-40 workers.

Feeding and Diet

Like other Lasius, this species is a generalist. It tends aphids for honeydew, especially Stomaphis hirukawai ^[4][5]. The Formicinae subfamily, to which it belongs, has strong mutualistic relationships with aphids (66.84% of all ant-aphid associations) ^[4]. In captivity, provide constant access to sugar water or honey, and offer protein-rich foods like fruit flies, small mealworms, or cricket pieces 2-3 times per week. Fresh protein is important during brood development.

Temperature and Seasonal Care

Maintain the nest around 20-25°C, which matches their forest habitat. A heating cable on one side creates a beneficial temperature gradient. Because Lasius productus is a temperate Japanese species, it likely requires a winter diapause. Provide 3-4 months at 5-10°C (November-February in the Northern Hemisphere) to simulate natural conditions ^[3]. Reduce feeding during diapause and avoid disturbing the colony. Resume normal care when temperatures rise in spring.

Behavior and Colony Dynamics

Lasius productus workers have extraordinarily long scapes and maxillary palps – the longest of any Lasius species, making them easy to identify ^[3][2]. They are relatively peaceful, focusing on foraging and aphid tending rather than territorial aggression. They are active mainly at dusk and night. Colonies grow moderately, the exact founding behavior has not been studied, but based on related species, a claustral founding phase lasting several months is expected. Once established, colonies can reach substantial (but unrecorded) sizes over several years.

Nuptial Flights and Reproduction

Nuptial flights occur in August and September, making this the latest-flying Japanese Lasius species ^[3][1][2]. Alates (winged reproductives) emerge in mid-summer, with flights peaking in late August through September. After mating, newly mated queens seek nesting sites in rotting wood or dead tree portions. If you wish to collect queens legally, search during this flight window. Their founding behavior is not directly documented, but it is likely claustral like other Lasius s.str. species.

Frequently Asked Questions

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References